Throughout much of the year, your Medicare plan selections are set in stone except under special circumstances. However, there is a limited window when anyone on Medicare can make changes.

Medicare's open enrollment period began on Oct. 15, 2022. But the clock is ticking: The open enrollment period ends on Dec. 7. This means that Medicare members only have three days left after today to make any of the following four changes.

A person looking at a calendar.

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1. Switch from Original Medicare to Medicare Advantage

Original Medicare includes hospital insurance covered under Medicare Part A and medical insurance covered under Medicare Part B. A little over half of Medicare members are enrolled in Original Medicare.

However, if you're thinking about switching from Original Medicare to a Medicare Advantage plan, you're not alone. Medicare Advantage enrollment has doubled since 2009.

Medicare Advantage plans are offered by private companies. These plans must at least match the services included with Original Medicare. However, they usually add Medicare Part D prescription drug benefits. Some Medicare Advantage plans offer vision, hearing, and/or dental benefits as well.

These additional benefits appeal to many Medicare members. Some Medicare Advantage plans also have lower out-of-pocket costs that can save you money. 

2. Switch from Medicare Advantage to Original Medicare

You could already be on a Medicare Advantage plan but would prefer to be on Original Medicare instead. If so, be aware of a few costs you might face if you drop Medicare Advantage during open enrollment.

For one thing, you'll probably want to add a separate Medicare Part D plan if you switch to Original Medicare. Otherwise, you'll have to foot the bill yourself for most prescription drug costs.

Your deductibles and coinsurance could also increase by moving to Original Medicare. These lower out-of-pocket costs put the "advantage" in Medicare Advantage in a big way. Because of these higher out-of-pocket costs, you might want to purchase supplemental Medigap insurance if you drop your Medicare Advantage plan. 

3. Change to another Medicare Advantage plan

Medicare Advantage plans differ when it comes to costs and benefits. If you're interested in finding a better plan to meet your needs, you don't have much time.

You'll definitely need to consider changing Medicare Advantage plans if you've recently moved. Your current plan might not include providers near where you now live in its network.

It's also possible that your primary physician has left the network of your current Medicare Advantage plan. If you want to keep your same doctor, you might have to switch to a different plan.

4. Enroll in, change, or drop a Medicare Part D plan

Healthcare in retirement can be more expensive than anticipated. Prescription drug costs are a big reason why. Medicare Part D plans offer a way to reduce your prescription drug costs.

If you aren't already covered by a Medicare Part D plan, now is the time to sign up. And if you are in a Medicare Part D plan, you might want to consider your options and potentially move to a different one that offers more attractive benefits and lower costs.

If you've moved, make sure you're still in your current Medicare Part D plan's service area. If not, you'll need to change plans.

Finally, if you don't think you need prescription drug coverage, you can drop your Medicare Part D plan during open enrollment. Just be aware that if you require expensive medications next year, you'll have to pay for them on your own. You won't be able to reenroll in Medicare Part D until Oct. 15, 2023, except in special cases.